Semi-dry electrode for electroencephalogram monitoring and preparation process thereof

Abstract

The invention discloses a semi-dry electrode for electroencephalogram monitoring and a preparation process thereof, the semi-dry electrode comprises a shell, a shell top, an electrode antenna, an electrolyte slow-release body and an electrode core, and the electrode antenna comprises a spring antenna and a hollow antenna; the electrolyte slow-release body is made of materials such as conductive sponge, conductive hydrogel or conductive fiber fabric, so that uniform release of the electrolyte is ensured; according to the preparation method, the three-dimensional modeling and 3D printing technology is adopted, the shape and size of the electrode are accurately controlled, the production cost is reduced, and the preparation time is shortened. The contact stability is improved by utilizing a combined structure of the spring antennas and the hollow antennas. According to the electroencephalogram semi-dry electrode, a more comfortable and controllable solution is provided for the electroencephalogram monitoring process, the flow speed of the electrolyte is adjusted through pressure, meanwhile, the spring antennas buffer the contact pressure, the wearing comfort is improved, the signal quality can be improved, and the wearing experience of a user is enhanced.

Description

Technical Field

[0001] The present invention belongs to the technical field of electroencephalogram (EEG) electrodes, and particularly relates to a semi-dry electrode for EEG monitoring and its preparation process. Technical Background

[0002] EEG electrodes, as key components of an electroencephalogram (EEG) acquisition system, have a development process closely linked to technological advancements in fields such as brain-computer interfaces, disease diagnosis, and human-computer interaction. Currently, EEG electrodes widely used in the market are mainly divided into three categories: wet electrodes, dry electrodes, and semi-dry electrodes.

[0003] Wet electrodes once dominated the field of EEG electrodes. Their advantage lies in being able to provide high-quality EEG signals. The conductive paste fills the tiny gaps between the electrode and the scalp, ensuring good electrical contact, making the signal stable and with low noise, which is crucial for research and clinical diagnosis that require precise analysis of EEG activities. However, the disadvantages of wet electrodes are also obvious. When using them, it takes a relatively long time to apply the conductive paste and wait for it to dry. This process is not only cumbersome but may also lead to unstable contact resistance due to uneven application or insufficient drying of the conductive paste, affecting the signal acquisition quality. In addition, during long-term use of wet electrodes, the conductive paste may gradually dry out or shift, further reducing the signal stability. In contrast, the advantage of dry electrodes is their convenience in use. They can be directly worn without any preparation, which makes them very attractive in wearable devices and real-time monitoring scenarios. However, due to the lack of a conductive medium, dry electrodes have a relatively large contact resistance with the scalp, resulting in generally lower signal quality than wet electrodes, especially in the acquisition of low-frequency signals, and are easily affected by external electromagnetic interference, limiting their application scope in high-precision EEG research.

[0004] Semi-dry electrodes, as a compromise solution, show certain advantages compared to wet electrodes and dry electrodes. By using special materials or designing unique structures, such as covering a layer of water-absorbing material on the electrode surface or setting up tiny liquid storage cavities, they can maintain the humidity between the electrode and the scalp to a certain extent, thereby improving the signal quality, while also avoiding the cumbersome preparation process of wet electrodes and being relatively convenient to wear. However, the current design of semi-dry electrodes still needs to be improved. First, the electrode structure made of hard material directly contacts the skin, and there is no buffer structure or material between the skin and the electrode, resulting in discomfort or even pain caused by long-term compression, seriously affecting the use comfort of semi-dry electrodes. Second, it is difficult to precisely control the release amount and speed of the electrolyte. If the release is too slow, it may lead to an increase in the resistance of the stratum corneum, affecting the signal quality; if the release is too fast, it may cause a short circuit between the electrodes. Summary of the Invention

[0005] The object of the present invention is to provide a semi-dry electrode for electroencephalogram (EEG) monitoring and its preparation process, so as to solve the technical problems that the existing semi-dry electrodes have difficulties in controlling the release rate and release amount of the electrolyte, the electrode structure causes skin discomfort to users, and the process of preparing EEG semi-dry electrodes is too complex.

[0006] The technical solution adopted by the present invention to solve its technical problems is: a semi-dry electrode for EEG monitoring, comprising: a housing, the housing is a hollow cylindrical shape without a cover at the top, and 3 to 5 liquid flow holes with a pore diameter of 0.5 to 1 mm are arranged in a circular pattern on the bottom plane thereof; The top of the housing, the top of the housing is a cylindrical lid with the same cross-sectional area as the housing, which is hermetically arranged above the housing, and includes a wire hole at the center of the top and an infusion hole offset from the center; Electrode tentacles, the electrode tentacles are arranged at the bottom of the housing and are equal in number to the liquid flow holes. Each electrode tentacle includes a spring tentacle and a hollow tentacle coaxially nested inside the spring tentacle. The cross-section of the spring tentacle is circular, and its center of the circle is located on the same vertical axis as the center of the liquid flow hole. The compression stroke of the spring tentacle is 2 to 5 mm; Electrolyte slow-release body, the electrolyte slow-release body is arranged inside the housing and is communicated with the liquid flow holes; Electrode core, the electrode core passes through the wire hole and is inserted into the electrolyte slow-release body; Wherein, the electrolyte flows into the hollow tentacle through the liquid flow hole and is slowly released to the skin surface through the holes at the bottom of the hollow tentacle. The spring tentacle is compressed under pressure to adjust the electrolyte flow rate and buffer the contact pressure at the same time.

[0007] Before use, the electrode is immersed in a container filled with electrolyte to make the electrolyte slow-release body absorb and saturate. During use, due to the pressure applied when wearing, the spring tentacles at the bottom first contact the skin surface. As the pressure is applied, the spring tentacles are continuously compressed until the hollow tentacles contact the skin surface. Under the action of gravity and the capillary force of the electrolyte slow-release body, the electrolyte slowly flows out from the holes at the bottom of the hollow tentacle, and the amount of electrolyte flowing out of each hole is the same. As the pressure changes, when the pressure is small, the contact impedance between the electrode and the skin is small, the release degree of the holes is the largest, and the amount of electrolyte flowing out is large and the flow rate is fast. When the pressure is greater, the contact impedance between the electrode and the skin becomes larger, the degree of blockage of the holes is larger, the amount of electrolyte flowing out is small, and the flow rate is slow. By using pressure, the effect of well controlling the amount and flow rate of the electrolyte is achieved, and the conductivity between the skin and the electrode is enhanced. During use, the electrolyte can be supplemented by injecting electrolyte through the infusion hole to maintain the persistence of EEG monitoring. The spring tentacles relieve the pressure on the skin during the compression process, improve the comfort, and can further improve the signal quality.

[0008] The described semi-dry electrode for electroencephalogram (EEG) monitoring has a liquid flow hole with a pore diameter of 0.5 - 1 mm, which is equal to the inner diameter of the hollow antenna, and the top plane of the hollow antenna is connected through the liquid flow hole.

[0009] The described semi-dry electrode for EEG monitoring has an electrolyte slow-release body selected from at least one of conductive sponge, conductive hydrogel or conductive fiber fabric, and the electrolyte contains at least one electrolyte among sodium ions, chloride ions or potassium ions.

[0010] The described semi-dry electrode for EEG monitoring has an electrode core which is one of a silver wire with a surface coated with Ag / AgCl, a metal disc or a conductive plastic disc.

[0011] The present invention also provides a preparation method for the semi-dry electrode for EEG monitoring, which is characterized by including the following steps:

[0012] Step 1: Use 3D modeling software to construct an electrode structure model, which includes an integrated design of a housing, a housing top and electrode antennas, and optimize the distribution of the liquid flow holes and the size of the electrode antennas through parametric modeling.

[0013] Step 2: Adopt a conductive ABS resin material and 3D print the electrode components by the fused deposition modeling (FDM) technology. The printing parameters are set as follows: layer height 0.1 - 0.2 mm, nozzle temperature 220 - 250 °C, printing platform temperature 80 - 100 °C, printing speed 200 - 300 mm / s.

[0014] Step 3: Assemble the printed housing, housing top and electrode antennas, and install the electrolyte slow-release body and the electrode core inside the housing.

[0015] The described semi-dry electrode for EEG monitoring has a hollow antenna which is a thin-walled round tube with a wall thickness of 0.5 mm.

[0016] The described semi-dry electrode for EEG monitoring has an electrode antenna with a height of 5 - 9 mm, and the ratio of the height of the hollow antenna to the height of the spring antenna is 1:1.5 - 1:2.

[0017] The described semi-dry electrode for EEG monitoring has its housing top fixed to the housing by adhesive bonding or screw connection.

[0018] The described conductive 3D printing material is selected from at least one of conductive ABS material, conductive PLA or conductive TPU.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention controls the flow rate and flow velocity of the electrolyte by setting a pressure control switch, enabling the uniform release of the electrolyte during the use of the semi-dry electrode, and achieving a good semi-dry effect of controlling the slow release of the electrolyte. The present invention buffers and absorbs part of the pressure during use by setting a spring antenna structure. During the use of the semi-dry electrode, the length is compressed and shortened, and the arc-shaped contact surface at the bottom of the spring antenna reduces pain, achieving a good effect of improving skin comfort. The present invention precisely controls the shape, size, and layout of the electrode by using 3D printing technology, improving the mechanical properties and conductivity of the electrode, while reducing production costs and shortening the production time. Description of the Drawings

[0020] Figure 1 is a schematic external view of the present invention; Figure 2 is a schematic structural view of the present invention; Figure 3 is a top view of the distribution of liquid flow holes at the bottom of the outer shell of the present invention; Figure 4 is a bottom view of the electrode antenna and the bottom of the outer shell of the present invention.

[0021] In the figure: 1. Outer shell; 101. Liquid flow hole; 2. Top of the outer shell; 201. Wire port; 202. Liquid infusion port; 3. Electrode antenna; 301. Spring antenna; 302. Hollow antenna; 4. Electrolyte slow-release body; 5. Electrode core. Detailed Embodiments

[0022] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application that is required to be protected, but only represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0023] For the convenience of description, the up and down directions in the present application are described based on Figure 1 the set direction shown. In Figure 1 , the semi-dry electrode for electroencephalogram monitoring is placed vertically downward, and this up and down direction does not limit the actual use direction of the semi-dry electrode for electroencephalogram monitoring.

[0024] Please refer to Figures 1-4, A semi-dry electrode for electroencephalogram monitoring in some embodiments of the present application includes: a housing 1, the housing 1 is a hollow cylindrical shape without a lid at the top, and there are 3 to 5 liquid flow holes 101 with a pore diameter of 0.5 to 1 mm arranged in a circular pattern on its bottom plane; The housing top 2, the housing top is a cylindrical lid with the same cross-sectional area as the housing, which is sealed above the housing, and includes a wire hole 201 at the center of the top and an infusion hole 202 offset from the center; The electrode antenna 3, the electrode antenna 3 is arranged at the bottom of the housing and has the same number as the liquid flow holes 101. Each electrode antenna includes a spring antenna 301 and a hollow antenna 302 coaxially nested inside the spring antenna 301. The cross-section of the spring antenna 301 is circular, and its center is on the same vertical axis as the center of the liquid flow hole 101, and the compression stroke of the spring antenna 301 is 2 to 5 mm; The electrolyte slow-release body 4, the electrolyte slow-release body 4 is arranged inside the housing 1 and is communicated with the liquid flow holes; The electrode core 5, the electrode core 5 passes through the wire 201 hole and inserts into the electrolyte slow-release body 4; Among them, the electrolyte flows into the hollow antenna 302 through the liquid flow hole 101 and is slowly released to the skin surface through the holes at the bottom of the hollow antenna 302. The spring antenna 301 compresses under pressure to adjust the flow rate of the electrolyte and buffer the contact pressure at the same time.

[0025] Before use, soak the electrode in a container filled with electrolyte to make the electrolyte slow-release body 4 absorb and saturate. During use, due to the pressure applied when wearing, the spring antenna 301 at the bottom first contacts the skin surface. As the pressure is applied, the spring antenna 301 continuously compresses until it contacts the skin surface together with the hollow antenna 302. Under the action of gravity and the capillary force of the electrolyte slow-release body, the electrolyte slowly flows out from the bottom of the hollow antenna 302 along the liquid flow hole 101. The amount of electrolyte flowing out of each hollow antenna 302 is the same. As the pressure changes, when the pressure is small, the contact impedance between the electrode and the skin is small, the release degree of the electrolyte is the largest, the amount of electrolyte flowing out is large, and the flow rate is fast. When the pressure is larger, the contact impedance between the electrode and the skin becomes larger, the degree of blockage of the electrolyte is larger, the amount of electrolyte flowing out is small, and the flow rate is slow. Through the pressure, the effect of well controlling the amount and flow rate of the electrolyte is achieved, and the conductivity between the skin and the electrode is enhanced. During use, the electrolyte can be supplemented by injecting electrolyte through the infusion hole 201 to maintain the persistence of electroencephalogram monitoring. By relieving the pressure on the skin during the compression of the spring antenna 301, while improving comfort, the signal quality can be further improved.

[0026] Among them, the number of the liquid flow holes 101 and the electrode antennas 3 is set according to actual needs. For example Figure 1Among them, 3 liquid flow holes 101 and electrode tentacles 3 are provided, but it is not limited thereto.

[0027] Among them, the parameters of the electrode tentacle 3 can be set according to actual needs. In this application, the hollow tentacle 302 is 5 mm high, with a pore diameter of 1 mm and a wall thickness of 0.5 mm, and the spring tentacle 301 is 9 mm high, but it is not limited thereto.

[0028] In some embodiments, the electrode core 5 is directly inserted into the internal part of the electrolyte slow-release body 4. The electrode core 5 passes through the wire hole 201 in the housing top 2 above the housing 1 and is connected to the wire connecting the electroencephalogram device, so as to realize the transmission of the electrical signal from the electrolyte slow-release body 4 through the electrode core 5 to the outside.

[0029] In this embodiment, see Figures 2-4 , the housing 1 is a hollow cylindrical shape without a lid at the top, and the housing top 2 is a cylindrical lid, which has the same circular cross-sectional area as the housing and is arranged above the housing to play a role in sealing the housing. There are two circular micropores on the housing top, namely the wire port 201 for connecting the wire and the infusion port 202 for supplementing the electrolyte during use. The housing 1 and the housing top 2 can be but are not limited to being connected by connection methods such as gluing and screw connection. The electrolyte slow-release body 4 is arranged inside the housing 1, and the electrode core 5 is arranged inside it and passes upward through the wire port 201 to be connected to the external electroencephalogram device. The slowly released electrolyte flows into the semi-dry interface formed between the electrode tentacle 3 and the skin along the liquid flow hole 101 at the bottom of the housing 1.

[0030] Among them, the sizes of the wire port 201 and the infusion port 202 are set according to actual needs. In this application, the diameter of the wire port 201 is 3 mm, and the diameter of the infusion port 202 is 2 mm.

[0031] Among them, the electrolyte slow-release body 4 can be selected according to actual needs, such as a conductive sponge that absorbs the electrolyte, or / and a conductive hydrogel, or / and a conductive fiber fabric. In this application, the electrolyte slow-release body 4 is a conductive sponge with high porosity and high conductivity, which can fully absorb the electrolyte, closely fit with the electrode core 5, and improve the electrical performance and the stability of electroencephalogram signal transmission.

[0032] Preferably, the electrode core 5 is made of a silver wire coated with Ag / AgCl on the surface, or / and a metal disc, or / and a conductive plastic disc, etc., but it is not limited thereto. Thereby, the reliability of the transmission of the electrical signal between the electrode core 5 and the electrolyte slow-release body 4 can be further ensured.

[0033] In some embodiments, a semi-dry electrode for electroencephalogram monitoring is made by the following method: Step 1: Use 3D modeling software to construct an electrode structure model. The model includes an integrated design of a housing (1), a housing top (2), and electrode tentacles (3), and optimizes the distribution of liquid flow holes (101) and the size of electrode tentacles (3) through parametric modeling; Step 2: Adopt a conductive ABS resin material and 3D print the electrode component through the fused deposition modeling (FDM) technology. The printing parameters are set as layer height 0.1 - 0.2 mm, nozzle temperature 220 - 250 °C, printing platform temperature 80 - 100 °C, and printing speed 200 - 300 mm / s; Step 3: Assemble the printed housing (1), housing top (2), and electrode tentacles (3), and install the electrolyte slow-release body (4) and the electrode core (5) inside the housing (1).

[0034] The embodiments described in the present invention are only preferred ways to achieve the purpose of the present invention, and do not limit the protection scope of the present invention. Without departing from the core idea of the present invention, any modification, equivalent replacement, improvement, or extension made by those skilled in the art to the present invention shall be regarded as within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims, covering all implementation manners and their applications directly or indirectly based on the technical solution of the present invention.

Claims

1. A semi-dry electrode for EEG monitoring, characterized in that: include: The housing (1) is in the shape of a hollow cylinder without a cover on the top, and has 3 to 5 liquid flow holes (101) with a diameter of 0.5 to 1 mm arranged circumferentially on the bottom plane; The top of the housing (2) is a cylindrical cover having a cross-sectional area equal to that of the housing (1), is sealed above the housing (1), and comprises a wire hole (201) located at the center of the top and an infusion hole (202) offset from the center; Electrode antennae (3), the electrode antennae (3) being arranged at the bottom of the housing (1) and being equal in number to the number of the liquid flow holes (101), each electrode antennae (3) comprising a spring antennae (301) and a hollow antennae (302) coaxially nested inside the spring antennae (301), the cross section of the spring antennae (301) being circular, the center of the spring antennae (301) being located on the same vertical axis as the center of the liquid flow holes (101), and the compression stroke of the spring antennae (301) being 2 to 5 mm; An electrolyte slow-release body (4), wherein the electrolyte slow-release body (4) is arranged inside the housing (1) and is connected to the liquid flow hole (101); An electrode core (5), wherein the electrode core (5) passes through the wire hole (201) and is inserted into the interior of the electrolyte slow-release body (4); The electrolyte flows into the hollow tentacle (302) through the flow hole (101) and is slowly released to the skin surface through the hole at the bottom of the hollow tentacle (302). The spring tentacle (301) is compressed under pressure to adjust the electrolyte flow rate and buffer the contact pressure.

2. The semi-dry electrode according to claim 1, characterized in that: The aperture of the liquid flow hole (101) is 0.5-1 mm, which is equal to the inner diameter of the hollow antenna (302), and the top plane of the hollow antenna (302) is connected to the liquid flow hole (101).

3. The semi-dry electrode according to claim 1, characterized in that: The electrolyte slow-release body (4) is selected from at least one of conductive sponge, conductive hydrogel or conductive fiber fabric, and the electrolyte contains at least one electrolyte selected from sodium ions, chloride ions or potassium ions.

4. The semi-dry electrode according to claim 1, characterized in that: The electrode core (5) is one of a silver wire, a metal disc or a conductive plastic disc coated with Ag / AgCl on the surface.

5. A method for preparing a semi-dry electrode for electroencephalogram monitoring, characterized in that: The following steps are involved: Step 1: constructing an electrode structure model using three-dimensional modeling software, wherein the model includes an integrated design of a housing (1), a housing top (2), and an electrode antenna (3), and optimizing the distribution of the flow holes (101) and the size of the electrode antenna (3) through parametric modeling; Step 2: Use conductive 3D printing materials to 3D print electrode parts using fused deposition modeling (FDM) technology. The printing parameters are set to layer height 0.1-0.2 mm, nozzle temperature 220-250 ° C, printing platform temperature 80-100 ° C, and printing speed 200-300 mm / s; Step 3: Assemble the printed shell (1), the shell top (2) and the electrode antenna (3), and install the electrolyte slow-release body (4) and the electrode core (5) into the shell (1).

6. The semi-dry electrode according to claim 1, characterized in that: The hollow feeler (302) is a thin-walled circular tube with a wall thickness of 0.5 mm.

7. The semi-dry electrode according to claim 1, characterized in that: The height of the electrode antenna (3) is 5 to 9 mm, and the ratio of the height of the hollow antenna (302) to the height of the spring antenna (301) is 1:1.5 to 1:

2.

8. The semi-dry electrode according to claim 1, characterized in that: The housing top (2) is fixed to the housing (1) by gluing or threading.

9. The method for preparing a semi-dry electrode according to claim 5, characterized in that: The conductive 3D printing material is selected from at least one of conductive ABS material, conductive PLA or conductive TPU.

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